1. Field of the Invention
This invention relates to a system for controlling the speed of a magnetic tape transport motor and, more particularly, to a system for controlling the speed of a magnetic tape transport motor using a microprogram.
2. Description of the Prior Art
The method of controlling the speed of a magnetic tape transport motor is known in the prior art, as for example in U.S. Pat. Nos. 3,293,522, 3,383,578 and 3,764,876. In the case where a magnetic tape controlling apparatus is provided with a a microcomputer containing a microprogram memory circuit, for performing various operating functions for controlling the tape, the speed of the control of the magnetic tape transport motor is achieved by an independent device.
However, in the prior art described above the following disadvantages exist. Firstly, the size and the price of the magnetic tape controlling apparatus cannot be reduced, because an independent device for controlling the speed of the motor must be provided. Secondly, the advantages which can be obtained by using a microprogram cannot be fully realized, because the microprogram does not include a program for controlling the speed of the motor. Thirdly, it is difficult to precisely control the speed of the motor in accordance with a predetermined controlling program of the magnetic tape controlling apparatus.